I’ve only played a few minutes of Zipper Interactive’s Unit 13 — enough to say that it’s a third-person tactical shooter for the Vita. It’s not SOCOM — that franchise emphasizes teams of players while Unit 13 focuses on pairs of players (either cooperatively or competitively). Going through a Direct Action mission with IGN’s Ryan Clements shows that Unit 13 hits all the basic points expected of a tactical shooter. Ryan and I can duck behind cover, we can use voicechat (I completely forgot that the Vita has a built-in mic), and blindly running and gunning results in quick death for the both of us.

Quite a bit has already been said about how the Vita’s form factor — now with dual analog sticks — makes it more conducive to first person shooters. Hey, you can aim and shoot! So those types of games can play as expected, rather than go through severe compromises like when they were on the PSP. That stuff is all fine and well, but it’s Unit 13′s more social functions that make it a title to watch.

Click the image above to check out all Unit 13 screens.

Unit 13′s core lies in its 36 short and replayable missions. Whether playing alone or in co-op, these missions shouldn’t take much longer than 10 minutes to get through, and you get scored upon completion. Again, the fact that this score feeds into unlocking weapons and perks and the like for your character isn’t particularly new or interesting — what’s interesting is how this score uses the Vita’s social functions.

When you complete a mission and get your score logged into the leaderboards (global, regional, and friends list only ones), said score gets pushed to your Unit 13-playing friends’ Activity Stream. That’s all well and fine, but let’s say a buddy plays that same mission and beats your score. That sort of news gets pushed to your Activity Stream, and you can jump right into that mission and reclaim your position on the leaderboard. These notifications can be pushed out via Near, Wi-Fi, or 3G (the latter means that you could theoretically just be on a train, get the notification, jump in, and update the leaderboards anywhere you have reception).

Okay, it’s not the newest idea — it sounds like a mix of both Autolog from the Need for Speed series and Battlefield 3′s Battlelog. Besides providing both notifications and opportunities to instantly jump into missions, Unit 13 does one other cool thing with the Activity Stream: use it to share unlocked missions with your friends.

Specifically, the more difficult High Value Target missions. As you play the other four mission types — Direct Action (a traditional objective-driven mission), Covert (a stealth oriented one), Deadline (a time-based one), and Elite (a high difficulty mission type that takes away checkpoints and health regeneration) — you earn stars for your performance. These stars then unlock High Value Target missions — single-player boss fights that end up being the toughest mission type. Whenever you unlock one of these, you can then share that mission to your friends (or anyone else close by with a Vita via Near). After you push it out, your friends have about three hours to complete the mission in order to score and keep it.

The developers at Zipper see this as a way for skilled friends to share content with you, but it presents a more interesting opportunity to me. If this takes off, I think more games should push content to friends and Near. Besides just unlocking missions, how about giving out gear in an action-RPG? Or player trades in sports games. Or sharing a track you made in ModNation Racers (to my knowledge, only “gift” items can be pushed out to friends and Near). While Unit 13 looks like a pretty solid shooter, it’s this social layer that piques my interest, and makes me hope that more Vita games copy this mechanic in the future.